new file mode 100644
@@ -0,0 +1,148 @@
+From 2ed6138dea0bc94c726f879501e4525712e885d1 Mon Sep 17 00:00:00 2001
+From: Stan Ulbrych <stan@python.org>
+Date: Sun, 10 May 2026 18:36:26 +0100
+Subject: [PATCH] gh-149018: Use `XML_SetHashSalt16Bytes` in
+ `pyexpat`/`_elementtree` when possible (#149023)
+
+
+CVE: CVE-2026-7210
+Upstream-Status: Backport [https://github.com/python/cpython/commit/24b8f12544468e4cedf5bfbe25442fcd495391e4]
+
+[yocto: Use weak symbol detection for XML_SetHashSalt16Bytes instead of
+XML_COMBINED_VERSION >= 20800, since our backported expat 2.6.4 provides
+the function but does not bump the version macros.]
+
+Signed-off-by: Amaury Couderc <amaury.couderc@est.tech>
+---
+ Include/pyexpat.h | 3 +++
+ Include/pyhash.h | 8 +++++---
+ .../2026-04-26-19-30-45.gh-issue-149018.a9SqWb.rst | 3 +++
+ Modules/_elementtree.c | 8 ++++++--
+ Modules/pyexpat.c | 22 ++++++++++++++++------
+ 5 files changed, 33 insertions(+), 11 deletions(-)
+ create mode 100644 Misc/NEWS.d/next/Security/2026-04-26-19-30-45.gh-issue-149018.a9SqWb.rst
+
+diff --git a/Include/pyexpat.h b/Include/pyexpat.h
+index 04548b7684a..d28d6828975 100644
+--- a/Include/pyexpat.h
++++ b/Include/pyexpat.h
+@@ -57,6 +57,9 @@ struct PyExpat_CAPI
+ XML_Parser parser, unsigned long long activationThresholdBytes);
+ XML_Bool (*SetAllocTrackerMaximumAmplification)(
+ XML_Parser parser, float maxAmplificationFactor);
++ /* might be NULL for expat < 2.8.0 */
++ XML_Bool (*SetHashSalt16Bytes)(
++ XML_Parser parser, const uint8_t entropy[16]);
+ /* always add new stuff to the end! */
+ };
+
+diff --git a/Include/pyhash.h b/Include/pyhash.h
+index 182d223fab1..ec359bd2f35 100644
+--- a/Include/pyhash.h
++++ b/Include/pyhash.h
+@@ -39,14 +39,14 @@ PyAPI_FUNC(Py_hash_t) _Py_HashBytes(const void*, Py_ssize_t);
+ * pppppppp ssssssss ........ fnv -- two Py_hash_t
+ * k0k0k0k0 k1k1k1k1 ........ siphash -- two uint64_t
+ * ........ ........ ssssssss djbx33a -- 16 bytes padding + one Py_hash_t
+- * ........ ........ eeeeeeee pyexpat XML hash salt
++ * eeeeeeee eeeeeeee eeeeeeee pyexpat XML hash salt
+ *
+ * memory layout on 32 bit systems
+ * cccccccc cccccccc cccccccc uc
+ * ppppssss ........ ........ fnv -- two Py_hash_t
+ * k0k0k0k0 k1k1k1k1 ........ siphash -- two uint64_t (*)
+ * ........ ........ ssss.... djbx33a -- 16 bytes padding + one Py_hash_t
+- * ........ ........ eeee.... pyexpat XML hash salt
++ * eeeeeeee eeeeeeee eeee.... pyexpat XML hash salt
+ *
+ * (*) The siphash member may not be available on 32 bit platforms without
+ * an unsigned int64 data type.
+@@ -71,7 +71,9 @@ typedef union {
+ Py_hash_t suffix;
+ } djbx33a;
+ struct {
+- unsigned char padding[16];
++ /* 16 bytes for XML_SetHashSalt16Bytes */
++ uint8_t hashsalt16[16];
++ /* 4/8 bytes for legacy XML_SetHashSalt */
+ Py_hash_t hashsalt;
+ } expat;
+ } _Py_HashSecret_t;
+diff --git a/Misc/NEWS.d/next/Security/2026-04-26-19-30-45.gh-issue-149018.a9SqWb.rst b/Misc/NEWS.d/next/Security/2026-04-26-19-30-45.gh-issue-149018.a9SqWb.rst
+new file mode 100644
+index 00000000000..d1b5b368684
+--- /dev/null
++++ b/Misc/NEWS.d/next/Security/2026-04-26-19-30-45.gh-issue-149018.a9SqWb.rst
+@@ -0,0 +1,3 @@
++Improved protection against XML hash-flooding attacks in
++:mod:`xml.parsers.expat` and :mod:`xml.etree.ElementTree` when Python is
++compiled with libExpat 2.8.0 or later.
+diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
+index 56d1508af13..941376613b0 100644
+--- a/Modules/_elementtree.c
++++ b/Modules/_elementtree.c
+@@ -3657,8 +3657,12 @@ _elementtree_XMLParser___init___impl(XMLParserObject *self, PyObject *target,
+ PyErr_NoMemory();
+ return -1;
+ }
+- /* expat < 2.1.0 has no XML_SetHashSalt() */
+- if (EXPAT(st, SetHashSalt) != NULL) {
++ // Prefer 16-byte entropy, only expat >= 2.8.0. See gh-149018
++ if (EXPAT(st, SetHashSalt16Bytes) != NULL) {
++ EXPAT(st, SetHashSalt16Bytes)(self->parser,
++ _Py_HashSecret.expat.hashsalt16);
++ }
++ else if (EXPAT(st, SetHashSalt) != NULL) {
+ EXPAT(st, SetHashSalt)(self->parser,
+ (unsigned long)_Py_HashSecret.expat.hashsalt);
+ }
+diff --git a/Modules/pyexpat.c b/Modules/pyexpat.c
+index 79492ca5c4f..47e3a1b2c00 100644
+--- a/Modules/pyexpat.c
++++ b/Modules/pyexpat.c
+@@ -14,6 +14,11 @@
+
+ #include "pyexpat.h"
+
++/* Use weak symbol to detect XML_SetHashSalt16Bytes at link time.
++ This allows using the backported function from expat even when the
++ version macros have not been bumped (e.g. expat 2.6.4 + CVE-2026-41080). */
++#pragma weak XML_SetHashSalt16Bytes
++
+ /* Do not emit Clinic output to a file as that wreaks havoc with conditionally
+ included methods. */
+ /*[clinic input]
+@@ -1388,10 +1393,16 @@ newxmlparseobject(pyexpat_state *state, const char *encoding,
+ Py_DECREF(self);
+ return NULL;
+ }
+-#if XML_COMBINED_VERSION >= 20100
+- /* This feature was added upstream in libexpat 2.1.0. */
+- XML_SetHashSalt(self->itself,
+- (unsigned long)_Py_HashSecret.expat.hashsalt);
++ /* Prefer 16-byte entropy (expat >= 2.8.0 or backported). */
++ if (XML_SetHashSalt16Bytes != NULL) {
++ XML_SetHashSalt16Bytes(self->itself, _Py_HashSecret.expat.hashsalt16);
++ }
++#if XML_COMBINED_VERSION >= 20100
++ else {
++ /* This feature was added upstream in libexpat 2.1.0. */
++ XML_SetHashSalt(self->itself,
++ (unsigned long)_Py_HashSecret.expat.hashsalt);
++ }
+ #endif
+ XML_SetUserData(self->itself, (void *)self);
+ XML_SetUnknownEncodingHandler(self->itself,
+@@ -2257,6 +2267,12 @@ pyexpat_exec(PyObject *mod)
+ #else
+ capi->SetHashSalt = NULL;
+ #endif
++ /* Detect at runtime via weak symbol */
++ if (XML_SetHashSalt16Bytes != NULL) {
++ capi->SetHashSalt16Bytes = XML_SetHashSalt16Bytes;
++ } else {
++ capi->SetHashSalt16Bytes = NULL;
++ }
+ #if XML_COMBINED_VERSION >= 20600
+ capi->SetReparseDeferralEnabled = XML_SetReparseDeferralEnabled;
+ #else
@@ -47,6 +47,7 @@ SRC_URI = "http://www.python.org/ftp/python/${PV}/Python-${PV}.tar.xz \
file://CVE-2026-11940.patch \
file://CVE-2026-11972.patch \
file://CVE-2026-9669.patch \
+ file://CVE-2026-7210.patch \
"
SRC_URI:append:class-native = " \